1. Field of the Invention
The present invention relates to a substrate processing apparatus having a dielectric disposed in an electrode so as to face a substrate, and a method of setting a thickness of the dielectric in the substrate processing apparatus.
2. Description of the Related Art
When wiring processes such as forming of holes, forming of trenches, and the like are performed on a substrate such as a semiconductor wafer, a fine process needs to be performed on the substrate, and thus, a dry etching process using plasma is being widely used.
Recently, in a method of processing a large-size substrate in which dry etching process is used, there have been studied various ways for uniformizing an etch rate throughout the entire surface of the substrate. For example, there has been suggested a method of compensating for non-uniformity of a voltage on an electrode plane by disposing a dielectric in an upper electrode in a chamber of a substrate processing apparatus including the upper electrode and a lower electrode (for example, refer to Patent Document 1). Silicon dioxide (SiO2) may be suitable to be used as the dielectric in consideration of a dielectric constant or availability.
On the other hand, in order to manufacture a semiconductor device by using a semiconductor wafer (hereinafter, simply referred to as wafer) as the substrate, a plurality of plasma processes need to be performed on one wafer. Thus, performing of a plurality of plasma processes while sequentially changing processing conditions in one chamber, that is, so called one-chamber plural processes, has been required recently.
However, since the one-chamber plural processes may sometimes include an etching process of a silicon dioxide film as an insulating oxide film formed on the wafer, the processing conditions in the chamber become suitable for etching the silicon dioxide when the insulating oxide film is etched by using the plasma. Consequently, the dielectric formed in the upper electrode may be etched and consumed fast. When the dielectric is consumed fast, cycles of replacing the dielectric or the upper electrode are reduced, and thus, CoC (cost of consumable) of the substrate processing apparatus degrades.    (Patent Document 1) Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2007-505450